CARDIAC SYSTEM MONITORING AND PROCESSING USING MATLAB

Presented BYAnindya Biswas Roll Number:- 11500313016 Arindam Das Roll Number:-11500313028Chinmoy Kumar Ghosh Roll Number:-11500313037

Amrita Das Roll Number:- 11500314118

BP PODDAR INSTITUTE OF MANAGEMENT AND TECHNOLOGY,KOLKATA

What to include

• How heart works• How the signal generated• ECG signal• Capturing the ECG signal• Challenges• Solution

CARDIAC MONITORING (ECG)

• ”electro”+ “cardio”+ “graph”= electrical activity + for heart + to write.

• Continuous recording of electrical activity of the heart.

•  Electrodes detect heart muscle's electrical depolarization pattern during each heartbeat.

• The overall magnitude of the heart's electrical potential is then measured and captured at each moment throughout the cardiac cycle.

• Heart disease kills one person in every 5 seconds – 7.6 M/yr of death worldwide each year (WHO)

• One common way to help diagnose for heart diseases

INTRODUCTION:

HEART DISEASES:

HISTORY Alexander Muirhead attached wires to a

feverish patient's wrist(1872).  Augustus Waller’s electrocardiograph

machine consisted of a Lippmann capillary electrometer fixed to a projector.

Willem Einthoven, working in Leiden, the Netherlands, invented the string galvanometer (the first practical ECG) in 1901.

In 1937, Taro Takemi invented the first portable electrocardiograph machine

EARLY PIONEERS :

BREAKTHROUGH :

MEDICAL USES

To measure the rate and rhythm of heartbeats.

To trace the size and position of the heart chambers.

To trace presence of any damage to the heart's muscle cells or conduction system.

Check the effects of cardiac drugs and the function of implanted pacemakers.

To detect Common types of heart problems –• Heart rhythm disorder: Irregular beats • Coronary heart disease: Cannot supply adequate circulation to cardiac

muscle cells. • Tachycardia: Heart beats very fast even whilst at rest.

PHYSIOLOGICAL FUNDAMENTALS• HEART:  Located in the middle of the thorax, slightly offset to the left composed of two atriums and two ventricles • HEARTBEAT: Number of beats from heart per unit of time (bpm). Can vary as the body’s need to absorb O2 and excrete CO2

changes.

ECG SIGNAL GENERATION• Cells in humans act like little batteries. • These cells have different ion concentrations inside and outside of their

membranes which create small electric potentials called biopotentials. • When there is a disturbance in a biopotential this gives rise to an action potential

which is the depolarization and repolarization of the cell as shown in Figure 1. • Essentially, the action potentials from different nodes in the heart are what make

up electrocardiograph (ECG) signals.

ECG SIGNAL• ECG: A Time-Varying Signal• Heart can be viewed as a time-varying voltage source • Net voltage amplitude = Sum of cardiac cell potentials • Voltage vary periodically based on cardiac cycle• Each event has a distinctive waveform • Waveform usually contains three distinct segments• ECG signals are comprised of the superposition of the different action

potentials from the heart beating as shown in Figure 2.

ECG SIGNAL CAPTURING• ECG machines use electrodes to convert the ionic signals from the body into electrical

signals to be displayed and used for data analysis. • General approach: Place electrodes at multiple places on the body surface – Measure potential difference across a lead (i.e. a pair of electrodes) – Exploit the fact that body tissue is a conductive medium that can relay cardiac

potentials • Commonly Used electrode- Ag/AgCl

CHALLENGES IN ECG ACQUISITION

• Due to the size of the signals and outside noise, ECG requires amplification and filtering to produce high quality signals.

• Raw ECG signals often low in amplitude and distorted by noise sources

• Magnitude range: 0.1 to 5 mV

• Sources Of Interference: 1) Internal Interference, 2) External interference

• Problem with having poor signal quality: Hard to obtain physiological insights – Low signal level => Difficult to detect – High noise level => May mask out useful clinical info.

GENERAL SOLUTION

• Aim: To boost the raw ECG signal level – Preferably without boosting the noise at the same time

• General Solution: Amplification And Filtering

• Approach: Amplify only the potential difference across two contact points and filter the desired output.

Circuit Design

Amplifier • Instrumentation Amplifier• Amplification of the weak signal

Filtering

• Reduction of noise and unwanted signal• Band Pass Filtering in ECG

Right Leg Drive ckt• Reduction of interference from the Amplifier• Inverts and Amplifies the average common mode

signal

Don’t Forget The MATLAB

• Matrix Laboratory• High Performance Language for Technical

Computing• Advantage Of using MATLAB• ECG signal processing using MATLAB

BIBLIOGRAPHY• Wikipedia• Google images• ‘Electrocardiography Circuit Design’--- project done

by NATHAN M KESTO(4/5/2013)• Other internet sources.

ACKNOWLEDGEMENT• Thank you to Dr. Arijit Saha , for giving us the

opportunity to do this creative project. All the information presented by me are correct as per my knowledge . We did my best to make the presentation errorless, but any kind of sincere advice from you to modify it is highly solicited…

THANK YOU ALL FOR GIVING YOUR PRECIOUS TIME